the protoss mothership got tweaked again and lost it's Blackhole skill (prolly reserved for the hero-class mothership that is avaiable only in campaign mode?)
in return, construction of the protoss mothership is not restricted to 1. The AoE projectile disruptor-like thingy can now be casted anywhere around the mothership within a specific range. Before it was a self-cast type of skill which can only stop certain projectiles from grazing the mothership's hull/shield.
also, the mothership acquired the SC1 protoss arbiter cloak skill. it's not a passive skill for the mothership though, so it's certain that it consumes energy over time.